Process for the oxidation of delta4-3-hydroxy-steroids to delta4-3-keto-steroids



United States Patent 1 2,911,403 PROGESSFOR OXIDATION OF A' -3-HY- DROXY-STEROIDS TO: A '-3-KETO S'I EROH)S Spndheimer, Jesus Romo, and George Roserikranz, Mexico City, Mexico, and CarliDjerassi, Birmingham, "Midli," assignor's, by mesne. assignments, to .Syntex S.A., Mexico City, 1 Mexico; a corporation of Mexico :No Diawing Application March 23,1953

Serial No. 344,246 7 Claims priority, application Mexico March 25, 1952 y 7 Claims. (Cl. 260-23955) The present invention relates to a novel process for the production of cyclopentanoplienanthrene compounds. Moreparticularly the, present invention relates to the oxidation ofsteroid hydroxy groups havinga double bond in (1,5 relation thereto.

In accordance with, the present invention it has been discovered that when steroids containing a double bond in 11,5 relation to a hydroxygroupare treated with manganese dioxide thev hydroxy group is oxidized. to a keto group even: though other hydroxy groups not so positioned in the molecule remain intact. It has further been discovered. in. accordance with the present. invention. that a similar reaction. may be carried out with Raney nickel catalyst in. the. presence of a hydrogen acceptor.

flThe process of the present invention is especially applicable to the oxidation of steroidal A -3-alcohols to the corresponding steroidal A -3-keto-compounds. andthe following equations, illustrate by way of example this oxidation:

HO-Q

' Hydrogen Acceptor Oxidatio Manganese dioxide or Raney nickel and Oxidation Manganese dioxide or Raney nickel and Hydrogen Acceptor Oxidation- Manganese dioxide or Y Raney nickel and- I Hydrogen Acceptor Oxidation Manganese dioxide or Raney nickel and Hydrogen Acceptor ice Although the above equations illustrate the conversion of steroidal A -3'-alcohols to AfiS-ketones, the same 11eac tions are applicable to other o e-unsaturated steroid'alcohols such as A -20-alcohols. the present invention the steroid alcohol is dissolved in a suitableorganic solvent. such asichloroform; hexane, or benzene and then shaken at-room: temperature: with. mam ganese dioxide for a substantial period of time,. as-,-for example for- 5 to' 24? hours. Althoughroomztemperature or slightly above as indicated is'preferred, higher; tem: peratures may beutilized to accelerate. the reaction;

' After the oxidation is. complete the. solutionis filtered and the filtrate evaporated to dryness. The-residue is then recrystallized from a suitable solvent.

Where Raney nickel isutilized: for: the oxidation indicated above, the steroid: alcohol is preferably dissolved I inthe hydrogen. acceptor which is preferably a ketone tained by the use of Raney nickelprepared according to the method of Mozingo (Organic Synthesis, 21, 15, 1941) or of Pavlic and Adkins (J.A.C.S.', 68, 1471).

It is to be noted further that the present process is generally applicable to the oxidation of steroidalhydroxy Preferably in practicing groups having a double bond in a,}3 position relative thereto irrespective of the configuration (a or [3) of these hydroxy groups. Further, that the compounds illustrated in the preceding equations and subsequent examples are intended only to illustrate typical examples of the sapogenin series, androstene series, pregnene series and cholestene series:

Example I A mixture of l g. of A -androsten3,17B-diol in 80 cc. of anhydrous chloroform and 10 g. 'of manganese dioxide previously dried over phosphorous pentoxide was shaken during 24 hours at room temperature and then the solution was filtered and evaporated to dryness. Recrystallization of the residue from acetone-hexane yielded 620 mg. of testosterone having a melting point of 151-l53 C. [eth l-112 (chloroform). The compound showed an ultraviolet absorption maximum at 242 m log E 4. 33. The identity of the product thus obtained was confirmed by comparison with an authentic sample of testosterone; the mixed melting point showed no depression and the infrared spectra were identical.

Example II Example III 500 mg. of A -pregnen-3, ZOB-diol dissolved in 50 cc. of chloroform were mixed with 5 g. of manganese dioxide previously dried over phosphorous pentoxide and the mixture was shaken for 24 hours at room temperature. After filtering and evaporating to dryness, the residue was crystallized from pentane to give 300 mg. of crystals with a melting point of 170173 C., [a] +89 (chloroform) which was identical to A -preguen-20fi-o1-3-one when compared with an authentic sample of this compound; the mixed melting point showed no depression and the infrared spectra were identical.

Example IV A solution of 2 g. of A -androsten-3, 17fi3-diol in 700 cc. of acetone was refluxed with 20 g. of Raney nickel for 6 hours. The catalyst was filtered and the solution was evaporated to dryness. The residue was subjected to a separation with Girard T reagent by the known method, and the ketonic fraction yielded 1 g. of testosterone which after recrystallization from ether-hexane had a melting point of 151-l52.

Example A solution of 1.5 g. of A -22-isospirosten-3-ol in 700 cc. of acetone was refluxed during 6 hours with 25 g. of Raney nickel prepared by the method of Pavlic and Adkins, previously referred to. The catalyst was filtered and the filtrate was evaporated to dryness. After reaction with Girard T reagent, 700 mg. of a ketonic fraction 4 were obtained. Recrystallization from acetone-hexane afiorded A -22-isospirsten-3-one with a melting point of 174-177 C.

Example VI A solution of 3 g. of A -pregnen-3, ZOfl-diol in 400 cc. of acetone was refluxed during 6 hours with 40 g. of Raney nickel. The catalyst was filtered and the solution was evaporated to dryness. By reaction with Girard T reagent 1.5 g. of a ketonic fraction was obtained. Recrystallization from methanol-water yielded A -pregnen- 2OB-ol-3-one (ZO-dihydroprogesterone) having a melting point of 166169 C.

Example VII A solution of 2 g. of A -cholesten-3-ol in 500 cc. of acetone was refluxed during 6 hours with 20 g. of Raney nickel prepared according to the method of Mozingo, previously referred to. After filtering the catalyst the solution was evaporated to dryness. Recrystallization from acetone-methanol gave 1.3 g. of A cholesten-3-one with a melting point of 78-80 C.

Example VIII A solution of 500 mg. of A -al1opregnen-3/3, 20fi-diol in cc. of benzene was mixed with 5 g. of manganese dioxide and then shaken at room temperature for 24 hours. The solution was filtered and evaporated to dryness. The crude product exhibited an ultraviolet ab sorption maximum at 236 mp (log E 3.7) thus indicating a 50% conversion to the A -20-ketone, i.e., A -allopregnen-3Ii-ol-20-one.

We claim:

1. A process for the production of a A -3-keto compound, said compound being otherwise unsubstituted or to the A double bond and selected from the group consisting of a A -3-keto androstene, a A -3-keto sapogenin and a A -3-keto pregnene which comprises oxidizing the corresponding A -3-hydroxy compound with manganese dioxide at room temperature.

2. The process of claim 1 wherein the product and starting material is a sapogenin.

3. The process of claim 1 wherein the product is A -22- isospirosten-3-one and the starting material is a A -22- isospirosten-B-ol.

4. The process of claim 1 wherein the product and starting material is a pregnene.

5. The process of claim 1 wherein the starting compound is a A -pregnen-3, 20fi-diol and the product is A -pregnen-20 8-ol-3-one.

6. The process of claim 1 wherein the starting material is an androstene.

7. The process of claim 1 wherein the starting compound is a M-androsten-S, 17fl-diol and the product is testosterone.

product and References Cited in the file of this patent UNITED STATES PATENTS Ehrenstein Nov. 21, 1950 Sondheimer et a1 Mar. 26, 1957 OTHER REFERENCES 

1. A PROCESS FOR THE PRODUCTION OF A $4-3KETO COMPOUND, SAID COMPOUND BEING OTHERWISE UNSUBSTITUED A TO THE $4 DOUBLE BOND AND SELECTED FROM THE GROUP CONSISTING OF A$4-3-KETO ANDROSTENE, A $4-3-KETO SAPOGENIN AND A $4-3-KETO PREGNENE WHICH COMPRISES OXIDIZING THE CORRESPONDING $4-3-HYDROXY COMPOUND WITH MANGANESE DIOXIDE AT ROOM TEMPERATURE. 